If you take a look at the actual physics, it is much more energy inefficient and takes much more energy to run that it does to bike. So if you wanted to ever get as much out of biking as you do out of running, you have to do much more biking than you run. This is because when you run you have to put your foot down, stop motion in that leg and move the other. That is why the best runners in the world want light shoes and look as though they are floating when running properly because they pick their foot up as quickly as possible. So it would be something around a 1:3 ration, running to biking. If you have the time and will power, biking is much easier than running and if done with the right ratio can achieve the same if not better results than running.